Chapter 3: The Science of Astronomy

What are keepers 3 laws of planetary motion?

1. the orbit of each planet is an eclipse with the sun at one focus 2. as a planet moves around its orbit, it sweeps out equal areas in equal times 3. more distant planets orbit the sun at slower average speeds, obeying the precise mathematical relationship p squared = a cubed

How is modern science rooted in ancient astronomy?

Ancient astronomers were accomplished observers who learned to tell the time of day and the time of year, to track cycles of the Moon, and to observe planets and stars. The care and effort that went into these observations helped set the stage for modern science.

In what ways do all humans use scientific thinking?

Scientific thinking relies on the same type of trial-and-error thinking that we use in our everyday lives, but done in a carefully organized way.

what is a scientific theory?

a simple yet powerful model that explains a wide variety of observations using just a few general principles, and that has survived repeated and varied testing

How did copernicus, tycho, and kepler challenge the earth-centered model?

copernicus created a sun-centered model of the solar system designed to replace the ptolemaic model, but it was no more accurate than ptolemy's because copernicus still used perfect circles. Tycho's accurate, naked-eye observations provided the data needed to improve on copernicus model. Kepler developed a model of planetary motion that fit Tycho's data.

how did galileo solidify the copernican revolution?

his experiments and telescopic observations overcame remaining objections to the Copernican idea of Earth as a planet orbiting the Sun. Although not everyone accepted his results immediately, in hindsight we see that Galileo sealed the case for the sun-centered solar system

how can we distinguish science from nonscience?

science generally exhibits three hallmarks: (1) modern science seeks explanations for observed phenomena that rely solely on natural causes (2) science progresses through the creation and testing of models of nature that explain the observations as simply as possible (3) a scientific model must make testable predictions about natural phenomena that would force us to revise or abandon the model if the predictions did not agree with observations

How did the Greeks explain planetary motion?

the greek geocentric model reached its culmination with the ptolemaic model, which explained apparent retrograde motion by having each planet move on a small circle whose center moves around Earth on a larger circle.

Why does modern science trace its roots to the Greeks?

the greeks developed models of nature and emphasized the importance of agreement between the predictions of those models and observations of nature